듣는 것이 많았다 or 들은 것이 많다?

I am currently reading the Korean idiom book on the left each morning while drinking my morning cup of coffee. It averages a little less than two idiom explanations per page, so it is the kind of book you can pick up and read for only five minutes a day and still benefit from. I usually spend about thirty minutes or more on it each morning.

I like the book, but I often get the feeling that the person explaining the Korean idioms has tried to write the explanations in an English style of Korean rather than a traditional Korean style. Several of the explanations seem awkward, at best. I am confused because the three people who collaborated on the book seem to be qualified, except that the person who actually wrote the explanations was an English Literature major rather than a Korean language major, which might explain the awkwardness.

Anyway, today I came across the following example sentence in the book that made me stop short:

견문이 넓은 그와 동무해서 일을 하다보니 듣는 것이 많았다.

Is 듣는 것이 많았다 correct? Shouldn't it be 들은 것이 많다? Doesn't it look like the writer was trying to write the Korean version of the English present perfect continuous or something?

Anyway, if I had written the sentence, I would have done it as follows:

• 견문이 넓은 그와 동무해서 일을 하다보니 들은 것이 많다.
  He is well-informed, and I have heard many things after becoming acquainted and working with him.